Dual Application of Ultrasound for Chlorella vulgaris Extraction of Bioactives and Pepper Seeds ( Capsicum annuum ) Priming with Agronomic and Biochemical R
Guilherme Arruda da Silva, Lucas Henrique Maldonado da Silva, Theisa Caroline de Assis, Marcia Regina Rodrigues Tanaka, Marciane Magnani, Tatiana Colombo Pimentel, Carlos Eduardo BarãoAbstract
Slow and non-uniform germination limits pepper (Capsicum annuum) stand establishment, demanding strategies that effectively enhance seed physiological performance. This study evaluated a two-step ultrasound-based approach combining ultrasound-assisted extraction of bioactive compounds from Chlorella vulgaris with extract-mediated sonopriming of pepper seeds. The extract selected for priming showed the highest phenolic content (28.37 mg GAE L–1) and indole-3-acetic acid level (1.722 µg mL–1). Seeds were sonoprimed under different ultrasound power–time combinations, and germination, vigor, seedling growth, and redox-related responses were assessed. Ultrasound conditions markedly affected seed performance, with 60% power for 20 min achieving ∼91% germination, the highest vigor (366.73), and the greatest seedling length (4.03 cm). Enhanced performance was associated with intermediate superoxide dismutase activity (∼350.03 U mg–1 protein) and a redox-related biochemical profile compatible with improved post-germination physiological status. Multivariate analysis supported a distinct and efficient sonopriming cluster, while SEM revealed localized seed-coat modifications without structural damage. Controlled ultrasound is therefore crucial for translating microalgal bioactives into physiological benefits.